Wildcat question

I have never seen either of these wildcats, nor do I have any information on either of them in any of my cartridge books; but I am sure one of them has to exist. For some reason, I have an insatiable desire to make .264 bullets go ultra fast. I have always said I am through with wildcatting and am not going through the hassle of developing any more of them. Having said that, I want a wildcat .264. Is there a .264 Wildcat in existence that has a full length 8mm Rem Mag or a full length 300WBY mag as the parent case? If so, what is it called, who makes reamers, and does anyone have any loading data?
Thanks in advance for any help.

Just as a note, I am well aware it will be a 500 shot or less barrel life wildcat.

I have read about at least three different versions of a 6.5STW but have never seen one in person. It's the 7mmSTW (the 8mmRemMag necked down to 7mm) necked down for .264 bullets.
Google turned up this page of one guy's version with a bit of load data. No info on reamers though.http://www.accuratereloading.com/65mmstw.html
Personally, I'd pick a different twist rate than what was used so it would work with heavier bullets too...but if you want a .264 1000-yd prairie dog rifle it sounds like the hot ticket.
In fact, I have seen a .257STW...about the same as necking it down to .264, it would also be a limited life barrel.

Another parent case that would be a similar or even larger capacity would be the .300 Remington Ultra Mag. There is a version called the .264 Ultracat.
The 7mm and .300 RUMs are a ridiculously inefficient pair based on the .404 Jeffery case. It would be mildly worse squeezed down to .264 or .257...but if it's already that far overbore in 7mm then what's another couple percentage points less efficiency right?

Do you have a copy of Ken Howell's "Designing and Forming Custom Cartridges for Rifles and Handguns"? You could get lost in that book for a long time. He does a good job of explaining the science of and his personal theories on wildcatting.
Like Gibbs, O'neil, Ackley, Neider and all the other "old-timers", Howell puts the ideas down on paper pretty well and is must-have reading material.

I have read about at least three different versions of a 6.5STW but have never seen one in person. It's the 7mmSTW (the 8mmRemMag necked down to 7mm) necked down for .264 bullets.
Google turned up this page of one guy's version with a bit of load data. No info on reamers though.http://www.accuratereloading.com/65mmstw.html
Personally, I'd pick a different twist rate than what was used so it would work with heavier bullets too...but if you want a .264 1000-yd prairie dog rifle it sounds like the hot ticket.
In fact, I have seen a .257STW...about the same as necking it down to .264, it would also be a limited life barrel.

Another parent case that would be a similar or even larger capacity would be the .300 Remington Ultra Mag. There is a version called the .264 Ultracat.
The 7mm and .300 RUMs are a ridiculously inefficient pair based on the .404 Jeffery case. It would be mildly worse squeezed down to .264 or .257...but if it's already that far overbore in 7mm then what's another couple percentage points less efficiency right?

Do you have a copy of Ken Howell's "Designing and Forming Custom Cartridges for Rifles and Handguns"? You could get lost in that book for a long time. He does a good job of explaining the science of and his personal theories on wildcatting.
Like Gibbs, O'neil, Ackley, Neider and all the other "old-timers", Howell puts the ideas down on paper pretty well and is must-have reading material.

Click to expand...

Thanks for the info. I will try to find a copy of the book. The .264 Stw sounds appealing. I guess I will dig into it further.

I'd settle for a 6.5-06 Ackley Improved , but I'm a sucker for the -06's

Click to expand...

I would probably go with the Hawk before the Ackley, but both are a slight step down from the Win mag which I already have three of. One is borderline needing a new barrel and after its rebarrel, it is no longer going to be a win mag.

Beat me to it jack. That would be my choice As it wouldnt require anything special from an action standpoint. a std .300 winmag action and a barrel short chambered for the 264 winmag. Either route you go would be a throat burner though. just make sure you go long on the barrel length to burn those monster loads of slow powder.

I find 26" about right for short action overbores like the .243 win to completely suck up a 40 grain charge of IMR4350, so with something like the .264 winmag thats gonna hold around 60 grains of the same powder, id go with at least a 30" barrel, but thats just me.

You guys are quite out of my league, I have a question re. throat burning. With the current wide variety of powders available and different burn rates ect.... Can the throat erosion be minimized compared to "back in the day" or is the problem basically the same?

You guys are quite out of my league, I have a question re. throat burning. With the current wide variety of powders available and different burn rates ect.... Can the throat erosion be minimized compared to "back in the day" or is the problem basically the same?

Humor me.

Click to expand...

For the most part Jack is right, overbore cartridges are just barrel burners, but with todays ever evolving powders and bullets you can to an extent prolong throat erosion by being selective with your powder. Usually in an overbore cartridge like the .243 they will be loaded with slower than youd think powders anyway, but it is possible, and I have seen it done to use an even slower powder to get a cooler burn, but the trade off is lack of efficiency and velocity loss. The best way to minimize throat eronsion IMO, is to shoot the heaviest bullets that your barrel will stabilize and use the slowest powder listed that gives a complete burn.

For the most part Jack is right, overbore cartridges are just barrel burners, but with todays ever evolving powders and bullets you can to an extent prolong throat erosion by being selective with your powder. Usually in an overbore cartridge like the .243 they will be loaded with slower than youd think powders anyway, but it is possible, and I have seen it done to use an even slower powder to get a cooler burn, but the trade off is lack of efficiency and velocity loss. The best way to minimize throat eronsion IMO, is to shoot the heaviest bullets that your barrel will stabilize and use the slowest powder listed that gives a complete burn.

Click to expand...

I used to take care of my barrels and try to baby them. I found that it makes less than 100 shot difference. The .264 I am about to re-barrel has conservatively estimating 600 shots on the barrel. Probably closer to 800. That is really not that bad for a hunting rifle that has lived its entire life shooting loads way over maximum. 95% or those shots were me playing around at the range. It still does not have to be re-barreled. It is about a 3/4" at 100 shooter, but it used to be 3/8" and is opening up pretty regularly. I could sell it and 99% of the people would not see anything wrong in the bore. They would even be thrilled with how it groups.

Like Us On Facebook!

The Firearms Forum is on online community for all gun enthusiasts. Join us to discuss firearms of all kinds, gun accessories, legal issues and more. Membership is free and we welcome all types of shooters, whether you're a novice or a pro. Come for the info, stay and make some friends.